1. Field of the Invention
The present general inventive concept relates to a hard disk drive, and more particularly, to a head slider having an improved floating property when the head slider is positioned on an inner circumference of a disk and a hard disk drive including the head slider.
2. Description of the Related Art
A hard disk drive (HDD) is an example of auxiliary memory devices used by computers, MP3 players, or mobile phones, and an apparatus that reads data stored in a disc, which is a data storage medium, or writes new data on the disk using a head slider which is a write/read medium of data. The head slider maintains a floating state by being lifted a predetermined gap from the disk during an operation of the HDD, and a magnetic head formed in the head slider reads data stored in the disk to reproduce the data or write new data on the disc.
The floating height of the head slider during the operation of the HDD is determined by an equilibrium height between a lifting force of the head slider due to air bearing between the head slider and a surface of the disk and a suspension elastic force that supports the head slider.
FIG. 1 is a plan view of a conventional head slider 15 floating over a disk 1 in a conventional HDD, and FIG. 2 is a plan view of the conventional head slider 15 that faces the disk 1.
Referring to FIGS. 1 and 2, an air bearing surface (ABS) pattern 25 to induce lifting of the conventional head slider 15 is formed on a surface of the conventional head slider 15 that faces the disk 1, and the ABS pattern 25 generally has a symmetrical shape with respect to a center line L1 (hereinafter, an ABS line) that denotes half of a face of the conventional head slider 15 that faces the disk 1. In a conventional head stack assembly (HSA) 10, the conventional head slider 15 is mounted on an end of the HSA 10 so that an imaginary line L2 (hereinafter, an HSA line L2) to connect a magnetic head 20 formed on the conventional head slider 15 to the rotation center C2 of the HSA 10, and the ABS line L1 can coincide.
The disk 1, which is a data storage medium, rotates at a high speed in a counter clockwise direction about a rotation center C1 during the operation of the HDD, and thus, an air flow in a counter clockwise direction is formed on the disk 1 due to the rotation of the disk 1. Such air flow enters the face of the conventional head slider 15 that faces the disc, and flows along the ABS pattern 25, and thus, generating a lift of the conventional head slider 15. A magnitude of the lift is related to a speed of the air flow and a shape of the ABS pattern 25. The speed of the air flow is proportional to a distance from the rotation center C1 of the disk 1. The ABS pattern 25 is designed to be maximally lifted when the direction of the air flow and the ABS line L1 are parallel.
When the conventional head slider 15 is located at middle circumferences 3 between inner circumferences 2 and outer circumferences 4 of the disc1, a straight line L4(ii) (hereinafter, an air flow line L4) extending in the direction of the air flow as indicated by the arrow W(ii) and the HSA line L2, that is, the ABS line L1, are parallel, and thus, a crossing angle between the air flow line L4(ii), indicated by the arrow W(ii), and the ABS line L1 is 0 degrees. Accordingly, the conventional head slider 15 maintains a stable floating state in the middle circumferences 3 of the disk 1.
When the conventional head slider 15 is located at a point of the outer circumferences 4 of the disk 1, an air flow line L4(iii) extending in the direction of the air flow as indicated by the arrow W(iii) is inclined with respect to the ABS line L1. Thus, a crossing angle between the air flow line L4(iii) and the ABS line L1 is greater than when the conventional head slider 15 is located in the middle circumferences 3. However, since the speed of the air flow in the outer circumferences 4 is greater than that of the air flow in the middle circumferences 3, the conventional head slider 15 can also maintain a stable floating state in the outer circumferences 4.
When the conventional head slider 15 is located at a point of the inner circumferences 2 of the disk 1, an air flow line L4(i) extending in the direction of the air flow indicated by the arrow W(i) is inclined in a direction opposite to the air flow line L4(iii) as described above. Thus, a crossing angle between the air flow line L4(i) and the ABS line L1 is greater than when the conventional head slider 15 is located at the middle circumferences 3 of the disk 1. However, in this case, since the speed of the air flow in the inner circumferences 2 is lower than that of the air flow in the middle circumferences 3, the lifting of the conventional head slider 15 is reduced. As a result, an instable floating of the conventional head slider 15 increases the contact (head-disk interference (HDI)) between the disk 1 and the conventional head slider 15.